The $40 billion project, scheduled to begin in December and take five years to complete, will install a canal 27.6 meters (90 feet) deep, no less than 230 meters (754 feet) wide, 173 miles between Punta Gorda on the Atlantic to Lake Nicaragua, and another from the lake westward to Brito on the Pacific Ocean.
Wang Jing, chairman of HKND, the builder, on Monday called the project "the biggest built in the history of humanity."
The Nicaraguan government said care taken in choosing the route would avoid harming the country's biodiversity, its indigenous territories and environmentally protected land. Revenues from the project could lift 400,000 out of poverty, it added.
The canal is meant to complement, not compete with, the Panama Canal, completed in 1914 and today too narrow for many ocean-going tanker ships.